Topology

Title: How to define the Torelli group of a surface with boundary?

Date: 10/24/2016

Time: 4:10 PM - 5:00 PM

Place: C304 Wells Hall

Speaker: Nikolai Ivanov, MSU

The Torelli group of a closed surface S is defined as the group of diffeomorphisms of S acting trivially on homology and considered up to isotopy. These groups naturally arise
in topology of 3-manifolds and in algebraic geometry. At the same time they are quite interesting groups by themselves. In order to study them, it is highly desirable to have also Torelli groups of surfaces with non-empty boundary. It turns out that the naive definition is not a good one.